There have been problems with the fitting of flange mounted automotive weatherstrips because of the manufacturing tolerances for both the weatherstrip and the vehicle. The flange to which the weatherstrip is fitted can have multiple thicknesses of sheet metal, and if the weatherstrip is pre-formed to accommodate these different thicknesses, it may be too wide for the single layer thicknesses and too narrow for the multiple layer thicknesses. As a result, the weatherstrip may not grip satisfactorily where the flange is of one layer, and if the flange consists of two or more layers, the weatherstrip may be extremely difficult to install in some places, and loose in others.
The weatherstrips have in recent years developed into complex cross-sections. They include the basic U-shaped central section, and optional internal ribs, and an embedded metal carrier which will maintain the shape of the central section. The weatherstrips are supplied to the assembly plant with the central section (and carrier) partially closed. This provides a cross-section with a low insertion effort for easy installation. This central section is applied to the vehicle opening flange by hand, beginning at some convenient index point. Various forms of lips and/or bulb sections may be provided on the exterior walls of the central section. A tool is then used to crimp the central section directly onto the flange.
The weatherstrips are fitted by an assembler in a loosely closed condition onto the opening (door) flanges on an assembly line, then formed by the tool to close the central section against the flanges, thus producing the desired final profile where the weatherstrip is tightly crimped in its functional position. This final forming operation is performed on line in the vehicle assembly plant utilizing a tool of the type disclosed herein. Thus, instead of a final stage of forming (as by rolls) at the end of the strip manufacturer's extrusion, as has been done in the past, and encountering the potential of distortion during packing and shipping, a hand-held roll-forming tool is used to post-form the weatherstrip directly onto the door flange, ensuring perfect sealing characteristics.
Present tools consist of a standard in-line pneumatic motor tool which drives two cylindrical counter-rotating rollers at its forward end. The necessary gears and bearings are housed in a case that is attached to the motor output shaft. The air motor is equipped with an activation lever which controls a valve in the air supply to the motor, to control rotation of the rollers.
The rollers are a predetermined fixed distance apart and revolve in opposite directions (e.g. an inward nip) thus applying pressure on the profile of the central section as these rollers are advanced along the weatherstrip already placed on the door flange. To use these tools correctly, the rollers must be kept in the correct relationship to the weatherstrip and flange during excursion of the tool around the opening. Specifically, the axes of the rollers must be maintained parallel to the flange surface. Also, the angle of the tool head should be kept at a certain inclination (e.g. inclined 5 degrees to 10 degrees towards the direction of travel) to start and maintain proper engagement of the rollers against the weatherstrip. If that inclination is too small or away from the direction of travel, then the tool will tend to move off the weatherstrip. The relatively heavy and off balance tool makes this action difficult and stressful.